Motion Sickness

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Description

  • Motion sickness is a physiologic response in affected individuals to a situation in which sensory conflict about body motion exists among visual receptors, vestibular receptors, and body proprioceptors.
  • Often induced when patterns of motion differ from those previously experienced or expected
  • Differs from “cybersickness” or “virtual reality sickness” (symptoms, including dizziness, that result from exposure to computer-based stimuli) in the fact that some form of actual movement is generally required to diagnose motion sickness
  • Systems affected: nervous, gastrointestinal (GI)
  • Synonym(s): car sickness; sea sickness; air sickness; space sickness; physiologic vertigo; kinetosis

Epidemiology

  • Females more likely to be affected than males (1)[C].
  • Pregnancy increases risk (possibly secondary to hormonal changes).
  • Children <2 years of age unlikely to be affected, although highest incidence in children 6 to 12 years of age

Prevalence

Estimation is complex although motion sickness is a common physiologic phenomenon that can develop in any individual with the right conditions. Estimations of prevalence vary widely by activity, from <1–1% of those riding in cars, trains or pressurized commercial aircraft to 25% of those traveling on large ships to up to 80% of astronauts during their first 3 days of space travel (1)[C].

Etiology and Pathophysiology

  • Precise etiology unknown; thought to be due to a mismatch of vestibular and visual sensations, particularly those to which an individual has not been habituated
  • Rotary, vertical, and low-frequency motions produce more symptoms than linear, horizontal, and high-frequency motions (2)[C].

Genetics

Heritability estimates range from 55% to 75% (1)[C].

Risk Factors

  • Motion (auto, plane, boat, amusement rides)
  • Visual stimuli (e.g., moving horizon)
  • Poor ventilation (fumes, smoke, carbon monoxide)
  • Emotions (fear, anxiety)
  • Zero gravity
  • Pregnancy, menstruation, oral contraceptive use
  • History of migraine headaches, especially vestibular migraine

General Prevention

See “General Measures.”Pediatric Considerations

  • Rare in children <2 years of age
  • Incidence peaks between 6 and 12 years of age.
  • Antihistamines may cause paradoxical agitation in children.
  • Scopolamine should be avoided in children.

Geriatric Considerations

  • Age confers some resistance to motion sickness.
  • Elderly are at increased risk for anticholinergic side effects from treatment.

Pregnancy Considerations

  • Pregnant patients are more likely to experience motion sickness.
  • Scopolamine should be avoided in patients with severe preeclampsia due to increased risk of eclamptic seizures.

Commonly Associated Conditions

  • Migraine headache
  • Vestibular syndromes

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